Flexible electrical conductor.



No. 730,847. PATENTED JUNE 9, 1903. L. VAN GILDER & ELM. POST.- FLEXIBLEELECTRICAL CONDUCTOR.

APPLICATION FILED NOV 8, 1902.

10 MODEL.

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UNITED STATES LINCOLN VAN GILDER AND EDWARD M. POST, OF PHILADELPHIA,PENN SYLVANIA, ASSIGNORS OF ONE-HALF TO HAROLD GODFREY AND OLIN TONGODFREY, OF PHILADELPHIA, PENNSYLVANIA.

FLEXIBLE ELECTRICAL CONDUCTOR.

SPECIFIOATION forming part of Letters Patent No. 780,847, dated June 9,190 3.

Application filed November 8, 1902. Serial No. 130,532- (No model.)

T aZZ whom it may concern:

Be it known that we, LINCOLN VAN GILDER and EDWARD M. POST, citizens ofthe United States,and residents of Philadelphia,Pennsyl- Vania, haveinvented certain Improvements in Flexible ElectricalOonductors, of whichthe following is a specification.

Ourinventionconsists of an improved form of fiexibleinsulated electricalconductor, hav- IO ing for its object the provision of an improved formof conductor which while being more flexible than other electricalconnecting means at present known to the art shall be much less liableto breakage or interruption I 5 of its electrical conductivity fromparting of a part or the whole of its conducting-body either fromprolonged use or rough treatment than has hitherto been the case. Thisobject we secure as hereinafter set forth, reference being had to theaccompanying drawings, in

which- Figure 1 is an elevation, partly in section, of 'a'portion of anelectrical conductor made according to our invention and illustratingthe method of the attachment of the conductor to a terminal of some formof electrical apparatus or to another conductor. Fig. 2 is an elevation,partly in section, showing .the application of our invention to awell-known form of electrical conductor at present in use. Fig. 3 is atransverse sectional. elevation of the conductor shown in Fig. 1, takenon the line 3 3 of said figure. Fig. i is a transverse sectionalelevation taken on the line 4: 4, Fig. 5 2; and Figs. 5 and 6 aretransverse sectional elevations of double conductors constructedaccording to our invention.

In certain classes of electrical work in which flexible electricalconductors are required it has been found to be absolutely essential inorder to secure satisfactory service that all of the individual strandsof said conductors remain unbroken, and with this object in view itis'cu'stomary to employ a conductor made of a large number of very finewires twisted or laid together and inclosed in a casing of suitableinsulating material. In the class referred to the breakage of even oneof these small strands of wire will give rise to a highlyobjectionableaction of the electrical appara- PATENT OFFICE.

which in the figures is shown as solid and proheld to the main portionof the conductor B metallic conductor a cannot under any pos- PatentedJune 9,1903.

tus in-circuit with the same, and for this reason as soon as it isdiscovered that such breakage of a small strand of the conductor hasoccurred the whole conductor is discarded, it being seen that thisnecessity greatly increases the cost of operation for such class ofelectrical devices. It is to overcome this difficulty that we havedevised our present improved conductor, and in the drawings abovereferred to A represents a flexible tube or conduit,preferably ofindia-rubber or other liquid-tight material, the interior of which isfilled with a solid and continuous column a, of mercury or, preferably,an amalgam of the same. In order to form electrical connection withanother conductor or to provide a terminal which -may be attached toelectrical apparatus, We provide a metallic piece B,

vided with a spherical head I), whose diameter is greater than theinternal diameter of the containing-tube A. After said tube has beenfilled with mercury or amalgam this rounded head is inserted into theend thereof, so as to press tightly against the liquid or semiliquidmaterial, and the tube is confined and tightly by means of a suitablewrapping or binding b, so that there is no possibility of escaping ofthe material from within the tube A, it being understood that thedrawings are intended to illustrate but one end of our improvedconductor, since the second end is in every Way similar to that shown.

Such a conductor as the above will have a flexibility only limited bythe flexibility of the tube A, and in view of the nature of the sibilityhave its conductivity interrupted by breakage, it being understood thatthe walls of the tube A have sufficient resisting power to Withstandcompression under operating conditions sufficiently to avoid variationof the conducting powers of the device from this cause.

By the use of a rubber tube, as above noted, as the container for theelectrical conductor of mercury or amalgam we secure a very materialadvantage, adding greatly to the value of our invention, such advantagebeing due o the fact that should the temperature of he said conductor becaused to rise from any nauseas, for example, from an excessive flow ofcurrent-the rubber tube would melt and by permitting the mercury oramalgam to flow out break the electric circuit through the same. Withthe well-known flexible conductors, in which plain cotton braiding isused to inclose rubber-covered wires, there is always danger of the saidbraiding catching fire from overheating of the conductors by tbnormallyheavy currents, whereas by the se of a rubber tube filled with a liquidor semiliquid conducting mass there is provided [5 means by which theelectric circuit will be broken before the said conductor has reached adangerously-high temperature.

Where it is desired, a stranded conductor a, of the ordinary form may beemployed within a flexible insulating-tube, as shown in Fig. 2, thestrands of said conductor being bent around the spherical head of theterminal connection B and electrically connected to the body thereof bya winding b The in- 5 ternal diameter of the tube A is in such case madegreater than the external diameter of the conductor a, and the cavity soleft is filled with mercury or amalgam, as before noted. l/Vith thisconstruction should break- 0 age of one of the small strands of the wireor cable a occur the liquid or pasty metal would immediately bridge suchbreak, so that there would be none of the varying resistance and theconsequent objectionable effects always occurring Where a strand of theconductor breaks under ordinary conditions in the class of work abovereferred to.

Where it is desired, a non-conductor of one or more strands of thread orcord may be em- 0 ployed within the flexible insulating-tube, thearrangement of this being the same as that shown in Fig. 2. The threadsof said nonconductor are attached to the spherical head of the terminalconnection B and run through 5 the tube in the same manner as whenmetallie wires are employed.

When either a conductor or non-conductor is employed, the extension orstretching of the flexible insulating-tube is prevented, as Q0 is alsothe separation into two or more portions of the contained pastyor liquidmetal by compression or bending, since channels are provided into whichthe mercury or amalgam may flow, the tendency being to hold the 5mercury or amalgam in place by the capillary action of the strands ofthe conductor or nonconductor, as the case may be,within the tube. Inpractical operation we preferably employ as our liquid or semiliquidconductor an o amalgam having a very decided viscosityas,

for example, sodium amalgam-so that unlike ordinary amalgams, a singlebody of this material is not easily divided into a number of otherbodies or masses, but tends to remain in a single mass, somewhatin thesame way as does molasses.

Where it is desired to provide a multiple 1 conductor, we employ theconstruction shown in Figs. 5 or 6 or a modification thereof, therebeing shown in the first of these figures two flexible rubber or otherinsulating tubes A, each containing in the structure illustrated astranded conductor a and filled with a liquid or semiliquid metallicconductor which completely surrounds said stranded conductor. These twoseparate devices A are then inclosed within a casing O, of woven fabricor other insulating covering.

Fig. 6 illustrates a form of the invention in which the insulating-tubesare concentrically arranged, there being a stranded conductor a placedaround the outside of a conductor of the construction shown in Figs. 1to 4 and within the space between the two tubes A and A, this space alsocontaining mercury or amalgam a We claim as our invention 1. Thecombination of a tube of non-conducting material having free ends,terminals projecting therefrom and a body of viscous amalgam interposedin said tube between said terminals, substantially as described.

2. The combination of a flexible insulatingtube, an electrical conductortherein containing mercury and terminals in electrical contact with saidconductor, with means extending longitudinally of the tube forpreventing elongation thereof,substantially as described.

3. The combination of a flexible insulatingtube, an electrical conductortherein containing mercury and terminals in electrical contact with saidmetallic conductor,with strands of inelastic material within the tubefor preventing elongation of the same, substantially as described.

4. The combination of a flexible tube of insulating material, a headedmetallic terminal extending into said tube and means engaging the tubeand confining it tightly to said terminal immediately beyond the head,the interior of said tube being filled with fluid conducting material inelectrical connection with the terminal, substantially as described.

5. The combination of an insulating-tube, a solid electrical conductortherein and a body of fluid electrical conducting material surroundingsaid solid conductor within the insulating-tube, the said conductingfluid being in electrical contact with the solid conductor,substantially as described.

6. The combination of an insulating-tube, a solid electrical conductortherein, metallic terminals extending into the tube in electricalcontact with the solid conductor and electricallyconducting fluidmaterial confined within the tube and surrounding and contacting withthe solid conductor, substantially as described.

7. The combination of an insulating-tube, a stranded metallic conductortherein and an electrical conductor containing mercury, surrounding andelectrically contacting with said stranded conductor within the tube,substantially as described.

8. The combination of a tube of insulating material, metallic conductorsextending into the same provided with means whereby said tube is heldtightly thereto, a solid metallictween said two tubes, substantially asdescribed.

10. The combination of a flexible insulating-tube, an electricalconductor Within the same,a second conductorsurroundingthe said tube anda second tube inclosing the whole with two independent bodies of anelectrical conducting material containing mercury as a base, surroundingsaid two conductors respectively, substantially as described.

1]. The combination of a tube of flexible insulating material with afluid metallic conductor of electricity therein, substantially asdescribed.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

LINCOLN VAN GILDER. EDWARD M. POST. Witnesses:

WILLIAM E. BRADLEY, J os. H. KLEIN.

